"the Universe Only Exists..."

[Barquentine]

Does anyone know who said: “The universe only exists because it is observed.”?

[Buenchico]

It's just a common reworking of the words of the Buddha:
""Within this fathom long body is the world, the origin of the world, the cessation of the world and the path leading to the cessation of the world".

So it forms part of (of interpretations of) Buddhist philosophy. Take a look at 'metaphysical solipsism' for the philosophical principle behind the argument:
https://en.wikipedia.org/wiki/Metaphysical_solipsism

It can also be seen as the basis for the anthropic principle:
https://en.wikipedia.org/wiki/Anthropic_principle

[JoJava]

Bishop Berkeley will get you started.

[ToraToraTora]

it's basically the weak anthropic principle, we are here because we are here!

[Colmc54]

Solipsism I believe.
https://en.wikipedia.org/wiki/Solipsism
You're either superstitious and are prepared to believe in stuff like life after death or you are rational and believe only that that can be proved to be real. You can't be both. One is rational the other is superstition. it doesn't matter which you choose as long as you don't brainwash others to make your choice and weaponise them to blow up secular rationalists like myself.

Happily science has beyond any rational or otherwise doubt proved that the observable universe existed billions of years before there was even life on this planet, let alone us humans with all our stupid superstitions and afterlife protection rackets.

Basic astronomical observations of what it was like long before we existed suggest that it will be there long after we, and all our stupid irrational belief systems such as 'reincarnation' a belief of Buddhism, become extinct.

[jomifl]

/ “The universe only exists because it is observed.”/

but not by us....perhaps.